Programming Forums > Application Development > C++

c_newbie · Mar 28th, 2006, 8:14 PM

hi . i am trying to output to a file using ofstream .. i'm down to 3 errors now : 'out' uses undefined class 'std::basic_ofstream<_Elem,_Traits>' also 'initializing' : cannot convert from 'const char [7]' to 'int' and error C2228: left of '.write' must have class/struct/union.
any help would be appreciated.
the code is below:

(Toggle Plain Text)

#include<fstream.h>
#include "stdafx.h"
#include<iostream>
#include<conio.h>
#include<string.h>
using namespace std;

class Person
  {
   private:
    int idNum;
    char name[10];
   public:
    Person(const int id, const char nm[]);
    friend ostream& operator<<(ostream& out,const Person &p);
    friend istream& operator>>(istream& in, Person &p);
	ostream& personDisplay(ostream &s);
  };
Person::Person(const int id = 000, const char nm[]="")
{
 idNum = id;
 strcpy(name,nm);
}
ostream& operator<<(ostream& out,const Person &p)
  {
    out<<p.name<<p.idNum<<endl;
    return(out);
  }
ostream& Person::personDisplay(ostream &s)
{
  cout<<"Here is a person: ";
  cout.setf(ios::left);
  cout.width(12);
  return(s);
}
istream& operator>>(istream& in, Person &p)
{
  cout<<"Enter ID Number ";
  cin>>p.idNum;
  cout<<"Enter name ";
  cin>>p.name;
  return(in);
 }

void main()
{
  Person aPerson;
  ofstream out("person.dat");   // change path if necessary
  cin>>aPerson;
  out.write((char*)(&aPerson), sizeof(aPerson));
}

Bench · Mar 28th, 2006, 8:44 PM

Change your #include files to C++ standard ones, Also change void main() to int main(). Finally, You can remove the stdafx.h if you like. You don't need that header since you can turn precompiled headers off in MS Visual C++

The following compiled with 0 errors in MSVC++ 2003 .NET

(Toggle Plain Text)

#include<fstream>
#include<iostream>
#include<conio.h>
#include<cstring>
using namespace std;

class Person
  {
   private:
    int idNum;
    char name[10];
   public:
    Person(const int id, const char nm[]);
    friend ostream& operator<<(ostream& out,const Person &p);
    friend istream& operator>>(istream& in, Person &p);
	ostream& personDisplay(ostream &s);
  };
Person::Person(const int id = 000, const char nm[]="")
{
 idNum = id;
 strcpy(name,nm);
}
ostream& operator<<(ostream& out,const Person &p)
  {
    out<<p.name<<p.idNum<<endl;
    return(out);
  }
ostream& Person::personDisplay(ostream &s)
{
  cout<<"Here is a person: ";
  cout.setf(ios::left);
  cout.width(12);
  return(s);
}
istream& operator>>(istream& in, Person &p)
{
  cout<<"Enter ID Number ";
  cin>>p.idNum;
  cout<<"Enter name ";
  cin>>p.name;
  return(in);
 }

int main()
{
  Person aPerson;
  ofstream out("person.dat");   // change path if necessary
  cin>>aPerson;
  out.write((char*)(&aPerson), sizeof(aPerson));
}

After-thought: you could have made that code a little simpler if you'd used the C++ <string> library

c_newbie · Mar 28th, 2006, 11:41 PM

Hey Bench
thank u so much .. really appreciate it .. u have no idea
thanx!

Ooble · Mar 29th, 2006, 9:47 AM

You'll want the cconio header instead of conio.h too.

InfoGeek · Mar 29th, 2006, 11:22 AM

I'm not sure, but I don't think there is a cconio header as conio.h is not a standard C header file.

DaWei · Mar 29th, 2006, 12:22 PM

Nice guess, though

.

c_newbie · Mar 29th, 2006, 2:42 PM

cool ..
ok i want to print the results on the screen and i am getting an error and/or "16"
do u guys know what code i should use ... i tried :

(Toggle Plain Text)

int main()
{
  Person aPerson;
  ofstream out("person.dat");   
  cin>>aPerson;
  cout<<((char*)(&aPerson), sizeof(aPerson)); //or
  aPerson.personDisplay;
  out.write((char*)(&aPerson), sizeof(aPerson));
  getch();
}

c_newbie · Mar 29th, 2006, 3:25 PM

its cool .. it was a no-brainer.. figured it out

Mar 28th, 2006, 8:14 PM	#1
c_newbie Newbie Join Date: Dec 2005 Posts: 14 Rep Power: 0	using classes, & fstream hi . i am trying to output to a file using ofstream .. i'm down to 3 errors now : 'out' uses undefined class 'std::basic_ofstream<_Elem,_Traits>' also 'initializing' : cannot convert from 'const char [7]' to 'int' and error C2228: left of '.write' must have class/struct/union. any help would be appreciated. the code is below: (Toggle Plain Text) #include<fstream.h> #include "stdafx.h" #include<iostream> #include<conio.h> #include<string.h> using namespace std; class Person { private: int idNum; char name[10]; public: Person(const int id, const char nm[]); friend ostream& operator<<(ostream& out,const Person &p); friend istream& operator>>(istream& in, Person &p); ostream& personDisplay(ostream &s); }; Person::Person(const int id = 000, const char nm[]="") { idNum = id; strcpy(name,nm); } ostream& operator<<(ostream& out,const Person &p) { out<<p.name<<p.idNum<<endl; return(out); } ostream& Person::personDisplay(ostream &s) { cout<<"Here is a person: "; cout.setf(ios::left); cout.width(12); return(s); } istream& operator>>(istream& in, Person &p) { cout<<"Enter ID Number "; cin>>p.idNum; cout<<"Enter name "; cin>>p.name; return(in); } void main() { Person aPerson; ofstream out("person.dat"); // change path if necessary cin>>aPerson; out.write((char)(&aPerson), sizeof(aPerson)); } #include<fstream.h> #include "stdafx.h" #include<iostream> #include<conio.h> #include<string.h> using namespace std; class Person { private: int idNum; char name[10]; public: Person(const int id, const char nm[]); friend ostream& operator<<(ostream& out,const Person &p); friend istream& operator>>(istream& in, Person &p); ostream& personDisplay(ostream &s); }; Person::Person(const int id = 000, const char nm[]="") { idNum = id; strcpy(name,nm); } ostream& operator<<(ostream& out,const Person &p) { out<<p.name<<p.idNum<<endl; return(out); } ostream& Person::personDisplay(ostream &s) { cout<<"Here is a person: "; cout.setf(ios::left); cout.width(12); return(s); } istream& operator>>(istream& in, Person &p) { cout<<"Enter ID Number "; cin>>p.idNum; cout<<"Enter name "; cin>>p.name; return(in); } void main() { Person aPerson; ofstream out("person.dat"); // change path if necessary cin>>aPerson; out.write((char)(&aPerson), sizeof(aPerson)); }

Mar 28th, 2006, 8:44 PM	#2
Bench Newbie Join Date: Feb 2006 Posts: 20 Rep Power: 0	Change your #include files to C++ standard ones, Also change void main() to int main(). Finally, You can remove the stdafx.h if you like. You don't need that header since you can turn precompiled headers off in MS Visual C++ The following compiled with 0 errors in MSVC++ 2003 .NET (Toggle Plain Text) #include<fstream> #include<iostream> #include<conio.h> #include<cstring> using namespace std; class Person { private: int idNum; char name[10]; public: Person(const int id, const char nm[]); friend ostream& operator<<(ostream& out,const Person &p); friend istream& operator>>(istream& in, Person &p); ostream& personDisplay(ostream &s); }; Person::Person(const int id = 000, const char nm[]="") { idNum = id; strcpy(name,nm); } ostream& operator<<(ostream& out,const Person &p) { out<<p.name<<p.idNum<<endl; return(out); } ostream& Person::personDisplay(ostream &s) { cout<<"Here is a person: "; cout.setf(ios::left); cout.width(12); return(s); } istream& operator>>(istream& in, Person &p) { cout<<"Enter ID Number "; cin>>p.idNum; cout<<"Enter name "; cin>>p.name; return(in); } int main() { Person aPerson; ofstream out("person.dat"); // change path if necessary cin>>aPerson; out.write((char)(&aPerson), sizeof(aPerson)); } #include<fstream> #include<iostream> #include<conio.h> #include<cstring> using namespace std; class Person { private: int idNum; char name[10]; public: Person(const int id, const char nm[]); friend ostream& operator<<(ostream& out,const Person &p); friend istream& operator>>(istream& in, Person &p); ostream& personDisplay(ostream &s); }; Person::Person(const int id = 000, const char nm[]="") { idNum = id; strcpy(name,nm); } ostream& operator<<(ostream& out,const Person &p) { out<<p.name<<p.idNum<<endl; return(out); } ostream& Person::personDisplay(ostream &s) { cout<<"Here is a person: "; cout.setf(ios::left); cout.width(12); return(s); } istream& operator>>(istream& in, Person &p) { cout<<"Enter ID Number "; cin>>p.idNum; cout<<"Enter name "; cin>>p.name; return(in); } int main() { Person aPerson; ofstream out("person.dat"); // change path if necessary cin>>aPerson; out.write((char)(&aPerson), sizeof(aPerson)); } After-thought: you could have made that code a little simpler if you'd used the C++ <string> library Last edited by Bench; Mar 28th, 2006 at 8:53 PM. Reason: Wrong include file

Mar 29th, 2006, 9:47 AM	#4
Ooble I eat cake for breakfast. Join Date: Jul 2004 Location: In my box. Posts: 4,434 Rep Power: 9	You'll want the cconio header instead of conio.h too. __________________ Me :: You :: Them

Mar 29th, 2006, 11:22 AM	#5
InfoGeek Professional Programmer Join Date: Jun 2005 Location: India, The great. Posts: 435 Rep Power: 4	I'm not sure, but I don't think there is a cconio header as conio.h is not a standard C header file. __________________ PFO - My daily dose of technology.

Mar 29th, 2006, 12:22 PM	#6
DaWei Resident Grouch Join Date: Jun 2005 Posts: 6,453 Rep Power: 10	Nice guess, though . __________________ Abstraction doesn't make it impossible to write bad code; it makes it possible to write superior code. Contributor's Corner: Grumpy on C++ Exceptions DaWei on Pointers

Mar 28th, 2006, 11:41 PM	#3
c_newbie Newbie Join Date: Dec 2005 Posts: 14 Rep Power: 0	Hey Bench thank u so much .. really appreciate it .. u have no idea thanx!

Mar 29th, 2006, 2:42 PM	#7
c_newbie Newbie Join Date: Dec 2005 Posts: 14 Rep Power: 0	cool .. ok i want to print the results on the screen and i am getting an error and/or "16" do u guys know what code i should use ... i tried : (Toggle Plain Text) int main() { Person aPerson; ofstream out("person.dat"); cin>>aPerson; cout<<((char)(&aPerson), sizeof(aPerson)); //or aPerson.personDisplay; out.write((char)(&aPerson), sizeof(aPerson)); getch(); } int main() { Person aPerson; ofstream out("person.dat"); cin>>aPerson; cout<<((char)(&aPerson), sizeof(aPerson)); //or aPerson.personDisplay; out.write((char)(&aPerson), sizeof(aPerson)); getch(); }

Mar 29th, 2006, 3:25 PM	#8
c_newbie Newbie Join Date: Dec 2005 Posts: 14 Rep Power: 0	its cool .. it was a no-brainer.. figured it out

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Programming Forums > Application Development > C++

using classes, & fstream